The total synthesis of a number of marine natural products in the polyketide and diterpene families will be undertaken. The targeted compounds exhibit high levels of growth inhibition against various human tumor cell lines but they are generally not readily available from natural sources in quantities amenable to their evaluation as drug candidates. In addition, we will synthesize analogues of some of the more active compounds that will be tested for differential cytotoxicity against tumor vs. normal human cell lines by Professor F. Valeriote at the Josephine Ford Cancer Center in Detroit. The main chemical issues to be addressed include the control of stereochemistry by means of chiral organometal chemistry and the design of new and efficient routes to structurally novel natural products.